High voltage vertical junction field effect transistors (VJFETs) built on Silicon Carbide (SiC) and other wide bandgap materials are of great interest for high power conversion applications due to their superior performance compared to similar devices built on Silicon (Si). Wide bandgap semiconductors have higher breakdown fields than Si that allows the use of thinner and more highly doped voltage supporting drift regions. This may directly result in many orders of magnitude reduction in device resistance in the on-state compared to a Silicon device of the same voltage rating.
VJFETs are unipolar devices since they use majority carriers and usually do not suffer from the problems related to minority carrier storage. VJFETs typically offer faster switching speeds and reduced switching losses. This allows for more compact power electronic circuits by reducing the size of the passive and cooling components. For unipolar devices the switching speed may be determined by the device capacitances. In hard-switched applications, such as most inductive loads like motors, low gate-drain capacitance (CGD) is critical for fast device performance.